clk: Don't dereference parent clock if is NULL

The clock passed as an argument to clk_mux_determine_rate_flags()
has the CLK_SET_RATE_PARENT flag set but it has no parent, then a
NULL pointer will tried to be dereferenced.

This shouldn't happen since setting that flag for a clock with no
parent is a bug but the core should be robust to handle that case.

Fixes: 035a61c314eb3 ("clk: Make clk API return per-user struct clk instances")
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Michael Turquette <mturquette@linaro.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 5469d7714f5d..f3a7a4425242 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -800,8 +800,8 @@ clk_mux_determine_rate_flags(struct clk_hw *hw, unsigned long rate,
         if (core->flags & CLK_SET_RATE_NO_REPARENT) {
                 parent = core->parent;
                 if (core->flags & CLK_SET_RATE_PARENT)
-                        best = __clk_determine_rate(parent->hw, rate,
-                                                    min_rate, max_rate);
+                        best = __clk_determine_rate(parent ? parent->hw : NULL,
+                                                    rate, min_rate, max_rate);
                 else if (parent)
                         best = clk_core_get_rate_nolock(parent);
                 else